In the present day scenario, it is observed that due to better medical facilities and better living conditions, the life span of the human population worldwide, has increased. Therefore, the average age of the human population worldwide is also on the rise. Even though the rising average age of the population is a positive development, however, it is also observed that with aging, certain health problems occur in the human body, in the natural scheme of things. Such health problems are inclusive of, but not restricted to, eye disorders. The human eye is an intricate and a very crucial organ. In this context, it is observed that, if there is a deterioration in the functioning of the eye, it can be very debilitating for an aging individual to conduct their day-to-day activities.
The deterioration in the functioning of the human eye can be due to a variety of eye disorders. Some of the commonly occurring eye disorders are inclusive of, but not restricted to, astigmatism, diabetic retinopathy, presbyopia, cataract, nystagmus, Keratoconus glaucoma and macular degeneration. The reasons for the occurrence of the eye disorders could be as wide as the range of the eye disorders. There may be different reasons for onset of the eye diseases. Aging, injury or damages to the eye parts may be the most prominent reasons. Some chronic diseases, including diabetes may cause eye troubles as well. Lack of vitamins can also contribute to eye diseases.
Regular usage of computers without keeping minimum distance, cell phones, video games, laptops, and watching high definition television with improper light source can also be treated as possible causes of eye disease. Today in modem times we rely on sophisticated technical gadgets to ease our work and unknowingly we suffer from eye fatigue or strain in eye muscles. This may also lead to permanent vision loss or temporary blindness. Anxiety, allergies and genetic factors are also responsible causes of eye disease. Environmental conditions like dry air or wind, dusty atmosphere and smoke also provokes eye problems.
In this context, in addition, it is also observed that, even though, the reasons for the occurrence of the eye disorders may be as wide as the range of the eye disorders, there are some predominant reasons inclusive of, but not restricted to, aging. It is also to be noted that, aging is not the only reason for the occurrence of all eye disorders, however, some of the eye disorders, like cataract, for instance, are predominantly attributable to ageing.
In this context, it would be pertinent to describe the internal structure of the eye. As it is already known, the eye is in itself, an intricate and a very crucial organ. A detailed examination of the internal structure of the human eye reveals that, the human eye is a ball-shaped structure. The human eye is inclusive of the following parts: The Sclerotic is the outer coating of the eye, which is white in color, protects the interior of the eye and also provides shape to the eye; the Cornea is the front part of the Sclerotic and is transparent to light, and also light coming from an object enters the eye through Cornea. The Iris is at the back of the Cornea. It is to be noted that, the eye lens is a double convex lens with the help of which image is formed at the retina by refraction of light. Space between cornea and eye lens is filled with a transparent fluid, called aqueous humor. Space between the eye lens and retina is filled with a jelly-like transparent fluid, called vitreous humor. Retina serves the purpose of a screen in the eye. Images of the object(s) are formed on the retina. Retina is at the back of the eye lens. It is well known to ophthalmic professionals that, “cataract” is an eye disorder which primary affects the eye lens. In medical terminology, the lens of the human eye is said to be afflicted with “cataract” when the lens of the eye, which is naturally transparent, becomes opaque, causing a progressive, painless loss of vision. The symptoms through which, cataract is recognizable are, in general, vision may be blurred, contrast may be lost, and halos may be visible around lights. The only treatment that provides a cure for “cataracts” is surgery. Occasionally, cataracts cause changes (such as swelling of the cataract or glaucoma) that lead doctors to recommend that, the cataract be removed quickly.
Conventionally, Phacoemulsification procedure is used for performing cataract surgeries. Phacoemulsification is a procedure in which the lens clouded by a cataract is broken up by ultrasound, irrigated, and suctioned out. It is known that, eye surgery is an intricate procedure, which requires a lot of meticulousness and attention, while the surgery is under progress, and also, in terms of post-operative care. However, it is also pertinent to note that, if the surgery is performed in an efficient manner, the outcome of the surgery is excellent, and the expected results are achieved. The excellent outcome of the surgery lies not merely in the dexterity of the eye surgeon, but also, in the instrumentation and medication deployed, for conducting the surgery. The said instrumentation includes, but is not limited to, the surgical tools such as, forceps, hooks, speculum, microscope, retinoscope, refraction box and the like, that are employed for conducting the surgery. Since, the eye is a fragile organ and any surgery involves observing the eye under a microscope, and concurrently performing the surgery in conjunction with an illumination system.
In this context it is pertinent to observe that, various types of operating microscopes are used for cataract surgery. With respect to the cataract operation conducted now, the conventional phacoemulsification process comprises irrigation and suction. The suction technique is a method of cutting the front capsule of a crystalline lens along the contour thereof, inserting a suction device from the cut edge, sucking the content of the whitish crystalline lens, and implanting an Inter ocular lens (IOL) therein in place of the sucked content.
When the suction technique is performed, an operating microscope is used for observation of the enlarged view of an eye to be operated. At this time of operation in order to improve the visualization, an image of Transillumination produced by the scattering and reflections from the retina of the eye is widely utilized. In particular, when the position of the cut edge in the front capsule is checked in order to insert the suction device and when it is determined whether or not the content of the crystalline lens is completely sucked, the red reflex is extremely effective. In such a scenario, it is also pertinent to note that, the illumination system employed is also a crucial component that is involved in the outcome of the surgery and hence, the outcome of the surgery depends to a certain degree, on the functioning of the illumination system. The efficiency of functioning of the illumination system includes, but is not restricted to, the lighting provided to illuminate the eye lens. The illumination system provides lighting, which is termed as “red reflex” and plays a major role in illuminating the natural eye lens, for the purpose of removal of the existing natural lens, and inserting the artificial intraocular lens. There are certain ancillary components also, for instance, the stable positioning of microscope employed for conducting the surgery. Even though, such ancillary components may seem insignificant, however, it is pertinent to note that, these components may play a small but significant role in increasing the excellence of the outcome of the eye surgery.
In order to obtain the red reflex suitable for an operator, various units have been proposed and executed up to now. As main examples of such units, there are “a Zero degree Illumination unit, in which a deflection mirror is disposed between the right and left observation optical axis of an objective lens and a complete co-axial illumination unit in which an illumination optical axis and observation optical axis is aligned with each other using a half mirror. However, in the zero degree illumination unit a region of red reflex resulting from an observation light flux in the right is different from that in the left. Therefore when the binocular vision is conducted, there is a problem in which good fusion of the image is not obtained. In addition, in the complete co axial illumination unit, because of a reduction in amount of observation light flux resulting from the use of the half mirror, only an entirely dark observation image can be obtained. Therefore, there is a problem in which the visibility is inferior.
An operating Microscope includes an Oblique mirror which deflects the emitted light from the source with an angle towards an eye to be operated. The angled illumination unit is generally constructed such that an angle of 2 deg for obtaining the red reflex and an oblique angle of 6 degree for obtaining a shadow contrast can be realized. The oblique angle particularly for obtaining the red reflex is within a range of about +/−0.5 deg is the condition following in other operating microscopes in market. In the illumination at such an angle is called “approximately coaxial illumination”. In the operation microscope using the angled illumination unit the following problems emerges, i.e., because an angle is provided between the illumination and the observation optical axis a region which is not irradiated with the illumination light is caused within the observable area of the retina and the part of the red reflex is not incident into the observation optical system. As a result a region in which the red reflex is not obtained is caused within an observation image.
Certain proposals are known in the art, which are directed towards similar application(s).
U.S. Pat. No. 5,790,306 titled Microscope beamsplitter, reveals a zonal beam splitter in the optical signal path for splitting the optical signal. The beam splitter comprises two right-angular prisms. A reflective element that occludes a portion of the optical path and reflects a portion of the optical signal path.
U.S. Pat. No. 7,907,336 titled Surgical microscope having an illuminating arrangement reveals an illuminating arrangement configured with illuminating light from one illuminating beam path, an illuminating spot/two illuminating spots can be generated on the retina of an ideal patient eye with said illuminating spot having a diameter lying in a range of 0.5 mm to 1.5 mm. Also, an illuminated field diaphragm is mounted to differentiate the optic images of one image plane from another.
U.S. 20110038040 titled Surgical microscope having an illuminating arrangement reveals a surgical microscope which is designed as an ophthalmologic surgical microscope. This surgical microscope has an illuminating arrangement with which an illuminating beam path can be adjusted with the illuminating beam path running coaxially to the stereoscopic viewing beam path. The Illuminating beam path is guided through the microscope main objective to the object region. For the purpose, a beam deflection unit is provided for the surgical microscope which is configures as a beam splitter. Preferably, the light exit section is the end of a light conductor. The Light exit section can, however, also be configured as a light source such as a light emitting diode, xenon lamp or a halogen lamp.
U.S. 20040227989 titled Microscopy system for eye surgery and method of illumination reveals a microscopy system, wherein the retro illumination system comprises a light source for generating of a light beam and a beam splitter for splitting the light beam into a beam of standard illumination light and the beam of retro illumination light such that the beam of standard illumination light is directed towards the object plane from the object lens side of the object plane, and wherein an angle between a main ray of the beam of retro illumination light and a main ray of the beam of standard illumination light is greater than 30.
U.S. Pat. No. 7,697,199 titled Lighting device and observation device reveals a lighting device described for an observation device, in particular for an ophthalmologic operating microscope, as well as such an observation device. The lighting device has a light source as well as a number of optical components, which are provided between light source and an objective element. The optical components are designed according to the invention in such a way that the imaging of the lighting pupil and the observation pupils is produced on the fundus of the eye.
U.S. 20110037947 titled Illumination device as well as observation device discloses an illumination device for an observation device comprising one, two or more observation beam paths with one respective beam of observation rays, especially for an ophthalmologic surgical microscope, and a corresponding observation device. Said illumination device is provided with at least one light source for generating at least one beam of observation rays in order to illuminate an object that is to be observed. According to one embodiment of the invention, at least two partial bundles of illumination rays are provided, each of which extends coaxial to a corresponding beam of observation rays, while the partial beams of illumination rays are embodied so as to form two or several illumination spots on the fundus of an object that is to be observed, e.g. an eye, said illumination spots having variable sizes, thus allowing the illumination beam to cooperate in a precisely defined manner with the observation beam paths, which makes it possible to meet especially the practical requirements regarding homogeneity of the red reflex.
DE 19650773 titled Illuminator for microscope for eye surgery esp. cataract operations reveals an illuminator having one deflector for the light arranged between the light source and the observation radiation path of the microscope. A second deflector device is also provided for the first light and is arranged closer to the observation radiation path than the first such device. The first deflector device comprises two components, of which one is fixed and the other is movable. The deflector component closest to the observation object is also provided with a deflector device on its side turned away from the light source, so that from this side the or a part of the light reflected in the direction of the observation object from the second deflector component is guided in the direction of the further deflector device.
U.S. 20110037948 titled White light emitting diode (LED) illuminator for ophthalmic endoillumination reveals an ophthalmic endoilluminator which includes one or more white light emitting diodes (LEDs), an additional light source, a first optical assembly, an optical coupling element, and an optical fiber optically coupled to the optical coupling element. The white LED is capped with a phosphor layer. The additional light source illuminates at least a portion of an exterior surface of the phosphor layer within an absorption band of phosphor material of the phosphor layer in order to excite the phosphor layer and produce additional white light. The first optical assembly receives and substantially collimates the white light. The optical coupling element receives the substantially collimated white light from the first optical assembly and directs the light to an optical fiber. The optical fiber is then used to conduct the white light into an eye.
U.S. Pat. No. 7,307,785 titled Lighting device and observation device reveals a microscopy system for eye surgery with an objective lens is suggested, which provides a retroillumination system to generate a so-called red reflex illumination during an eye-surgical treatment, in particular, during a cataract operation.
It is observed that, the known proposals do not solve requirement(s), which are specific to increasing the excellence of the outcome of the eye surgery, and thereby reduce the probability of post-operative problems for the patients as well as for the ophthalmic professionals.
Further, there is a problem in the available state of the art that the light source used generates heat in addition to light and is not efficient as a result. In the case of eye surgery, heat generated by the light source may not only mean mere wastage of energy but is also detrimental to the outcome of the surgery since the human eye is a delicate organ and excessive heat energy being present in the vicinity of the eye may have detrimental effect on the eye, while it is being operated on and also in the post-operative stage.
There is still the problem that the light source used in the illumination system generates light of wavelengths, which are very much outside the visible spectrum, like ultraviolet rays and infrared rays. Since production of such rays is detrimental to the eye an additional light filter component is deployed. This additional component means that cost and maintenance of the illumination system is increased.
There is still the problem that usage of a beam splitter component causes generation of secondary reflections. Such an optical defect decreases the efficiency and is detrimental to the overall outcome of the eye surgery since the surgeon is likely to be distracted.
There is still the problem that the mechanical components deployed for stability of the microscope are not robust. Therefore the overall outcome of the surgery may not be as desired.
In the described context, it will be amply clear to a person skilled in the art that in view of the above-mentioned problems there is a need in the art for an illumination system in which the characteristics of the light source used is not detrimental to the excellent outcome of the surgery since the human eye is a delicate organ and is susceptible to heat, and therefore excessive heat generated by the light source in the vicinity of the eye may have detrimental effect on the delicate internal structure of the eye, while it is being operated on and also afterward in the post-surgical stage.
It will also be amply clear to a person skilled in the art that in view of the above-mentioned problems there is a need in the art for an illumination system in which the wavelength characteristics of the light source used in the illumination system does not generate light of wavelengths, which are toxic to the eye since production of such rays is detrimental to the eye. To mitigate the detrimental effect of such rays on the eye conventional proposals require an additional light filter component to be deployed. However installation of such a filter component means that cost and maintenance of the illumination system is increased.
There is therefore a requirement in the art for an illumination system in which the wavelength characteristics of the light source used in the illumination system does not generate light of wavelengths, which are toxic to the eye since production of such rays is detrimental to the eye. The need in the art is for an illumination system, which does not require the installation of a filter component.
There is therefore a requirement in the art for an illumination system in which usage of a beam splitter component should not cause generation of secondary reflections. Such an occurrence decreases the efficiency and is detrimental to the overall outcome of the eye surgery since the surgeon is likely to be distracted due to the secondary reflections.
There is therefore a requirement in the art for an illumination system in which the mechanical components deployed for stability of the microscope are robust and the instrumentation employed by the surgeon is stable. Such an arrangement will ensure that the results of the eye surgery performed are excellent and the results are satisfactory to both the patient and the surgeon alike.